1. Field of the Invention
This invention relates to a structure of a fuel injection valve for injecting fuel directly into a combustion chamber in an internal combustion engine.
2. Description of the Related Art
In a fuel injection valve of the type attached to a cylinder head of an internal combustion engine for injecting fuel directly into a combustion chamber, the fuel must be appropriately sprayed into the combustion chamber. As one means therefor, there was an apparatus in which a swirler gives swirling energy to a fuel flow to be injected so that fuel is injected from a fuel injection hole.
Japanese Patent Unexamined Publication No. Sho. 64-36972 discloses a conventional fuel injection valve. In FIG. 10A and 10B, a moving valve 101 is driven vertically by an electromagnetic drive means to be separated/contacted from/with a conical seat surface 105b of a valve guide 105 so that the valve is opened/closed to thereby inject fuel from a fuel injection hole 105a. On the other hand, a swirler 102 having a conical surface at the same angle as that of the seat surface 105b is disposed on the conical seat surface 105b of the valve guide 105. Two or more volute fuel grooves 102b are spirally formed in an outer circumferential portion of the swirler 102. The moving valve 101 is slidably disposed in a through-hole 102a along the center axis of the swirler 102. An elastic member 103 is interposed between the bottom surface of the conical surface of the swirler 102 and a stopper 104 integrally fixed to a yoke 107 so that the swirler 102 is urged toward the conical seat surface 105b by the elastic member 103.
In the apparatus depicted in FIGS. 10A and 10B, fuel introduced through a fuel passage of the yoke 107 passes through a stopper 104, a passage 103b of the elastic member 103 and is injected into a cylinder of an engine from the fuel injection hole 105a of the valve guide 105 through the fuel grooves 102b of the swirler 102. That is, a fuel flow is given swirling energy through the swirling grooves 102b, narrowed by the fuel injection hole 105a of the valve guide 105, atomized, and injected.
In the conventional fuel injection valve, the swirler for giving swirling energy to a fuel flow is generally machined and produced by cutting machining, or the like. In the case where such cutting is used, however, there arises a problem that the cost of production becomes high even if mass-production is carried out.